bundlespec: allow the bundle spec to control the bundle version
This makes it possible to create bundle using changelog-v3.
The `hg debugbundle --spec` output is borked, but this will be fixed in coming
changesets.
[build-system]
requires = ["setuptools", "wheel"]
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true